Well drilling apparatus

ABSTRACT

Drilling apparatus in which the motive force for the drill bit comprises a fluid motor disposed relatively close to the drill bit, the fluid motor comprising a pair of helicaL gears fitted one within the other, the outer gear having internal helical threads and comprising the rotor to which the drill bit is connected, the inner gear having external threads and being fixed against rotation, the arrangement being such that the inner gear is free to gyrate when driving force flows between the gears so that the outer gear member and the attached drill bit will rotate in a concentric path. Apparatus in accordance with the invention may be used in land drilling operations or adapted for use in underwater drilling operations, such adaptations including the use of a drill support and a flexible connection to a platform or workboat situated above the drilling site.

O United States Patent 1 3,603,407

[72] Inventor Wallace Clark 2,898,087 8/1959 Clark 175/99 1830 S. German Church Road, 3,129,774 4/1964 Armstrong 175/107 X Indianapolis, Ind. 46239 3,260,318 7/1966 Neilson et al.. 175/107 X [21] Appl. No. 888,711 3,353,612 11/1967 Bannister 175/6 {22] Filed Dec. 29,1969 3,370,656 2/1968 Grolet et a1 175/6 [45] Patented Sept. 7,1971

Continuation-impart of application Ser. No. jg'gfzffifi l ggfir ag 2:3 1968' now abandoned' Attorney-Melville, Strasser, Foster and Hoffman ABSTRACT: Drilling apparatus in which the motive force for [54] WELL DRILLING APPARATUS the drill bit comprises a fluid motor disposed relatively close to the drill bit, the fluid motor compnslng a pair of hellcaL 18 Claims, 10 Drawing Figs.

gears fitted one within the other, the outer gear having inter [52] US. Cl [75/6, h li al threads and comprising the rotor to which the drill I75/107 bit is connected, the inner gear having external threads and [5 l llll. Cl E2") 7/12 being fixed against rotation the arrangement being such that [50] Field Of Search 418/48, the inner gear is free to gyrate when driving force flows 22 1 2, 99, 6 between the gears so that the outer gear member and the attached drill bit will rotate in a concentric path. Apparatus in [56] References cued accordance with the invention may be used in land drilling UNITED STATES PATENTS operations or adapted for use in underwater drilling opera- 2,250,9l2 7/1941 Hudson et a1 175/99 tions, such adaptations including the use of a drill support and 2,665,885 1/ 1954 Gignoux 175/6 a flexible connection to a platform or workboat situated above 2,669,431 2/1954 Crowell 175/8 X the drilling site.

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ATTOR N EYS PATENTEDSEP 7|97| 3.6034407 sum 3 [1F 3 lNVENTOR/S WALLACE CLARK,

BY QM TZZSMWW WELL DRILLING APPARATUS This is a continuation-in-part of copending application Ser. No. 705,436, filed Feb. 14, 1968 now abandoned and entitled DRILLING APPARATUS.

BACKGROUND OF THE INVENTION It was hitherto proposed in U.S. Pat. No. 2,898,087, issued to the present inventor, to provide a liquid motor to drive the drill. bit, the motor being mounted in close proximity to the drill bit. The motor used in the drilling apparatus described in the said patent includes a pair of helical gears, such as are disclosed and claimed in US. Pat. Nos. 1,892,217, and 2,028,407, hereinafter referred to as the Moineau patents. Devices constructed in accordance with the Moineau patents have become commercially well-known in the form of pumps and compressors marketed under the trademark MOYNO, by Robbins & Myers, Inc., of Springfield, Ohio. Essentially, the Moineau devices comprise inner and outer gears, the outer gear being a fixed element having internal helical threads, with the inner gear comprising a rotor element having at least one external thread, such that the outer element or stator has one more thread than the rotor. In the Moineau pumps mentioned above, it has been conventional for the stator to have a double thread while the rotor has a single thread. When these devices are used as pumps, motive power is applied to the rotor and a series of pumping pockets defined between the rotor and stator move longitudinally through the device to convey the fluid being pumped. When used as a motor, as taught in the aforementioned U.S. Pat. No. 2,898,087, a fluid is pumped through the device, whereby the rotor or inner gear is caused to turn with respect to the stator. In addition, a connecting rod is provided between the drill bit shaft and the rotor, the connecting rod including a double universal joint to compensate for the fact that the rotor rotates upon an axis eccentric to the axis of the stator and gyrates in a cylindrical path. Thus, in the drilling operation the rotor of the motor was the driving force for the drill bit. It has since been proposed to connect the rotor directly to the drill bit and mount the drill bit so that it too will gyrate, thereby further simplifying the mechanism required for the drilling operation. However, in either case, problems have developed which have resulted in excessive wear or vibration, or the binding of the drill bit, particularly where stabilizers were employed to accurately align the drill assembly relative to the drill hole. The present invention overcomes the problems encountered in the prior art and provides a simplified yet workable system which materially reduces wearand tear on the drill assembly, including the drill bit, and acts to smooth out the entire drilling operation as well as cure lubrication problems.

SUMMARY OF THE INVENTION The present invention will find utility in both coring and drilling operations, and may be used in both land or underwater drilling operations. Briefly, in the practice of this invention, the drill bit is connected to one end of the outer gear of the helical gear motor. The inner gear of the motor is fixed against rotation, although it remains free to gyrate in a circular path, such that the passage of a driving fluid through the pockets defined between the gears causes the outer gear to rotate and hence rotate the drill bit.

This arrangement eliminates or at least materially reduces the problem of wear which typically occurs in conventional drilling with a down-hole motor at the thrust bearing between the rotating drill bit and the surrounding stationary casing. That is, by rotating the entire casing, including the outer gear member, it is possible to effectively avoid the wear caused by the axial pressure of the normal drill string. in a drilling assembly such as that taught in US. Pat. No. 2,898,087, the connecting rod is in compression, whereas in accordance with the present invention the connecting rod will be in tension and consequently a much lighter and less expensive rod may be employed. Alternatively, the connecting rod may be replaced by a twisted cable or a torsion bar, in which event the universal joints ban be eliminated. Where a tension member is employed, it may be longer than a conventional rod, thereby reducing the effective angle between the two members it joins and hence the amount of eccentricity for which it must compensate per unit of length.

Where the entire motor casing is rotated, more efficient drilling results in that a flywheel effect is realized which materially smooths out the drilling operation and results in less wear and tear on the equipment and on the drill bit. In particu lar, the bit is far less likely to fracture, especially where a diamond bit is employed which will shatter when subjected to shock.

A drill assembly in accordance with the present invention also permits the use of stabilizers immediately adjacent the drill bit. Such stabilizers normally comprise fins or rollers projecting outwardly from the drill assembly for contact with the wall surface of the drill hole. The stabilizer may or may not turn with the casing, but the latter is preferred because of less drag against rotation. In a conventional down-hole motor drilling assembly, if stabilizers are employed at the lowermost end of the casing adjacent the drill bit, binding will occur if the bit begins to walk, i.e., move laterally. As a result, in conventional assemblies the stabilizers have been usually limited to the upper end of the drill assembly, which may be as much as 10 or more feet from the drill bit. With the structure of the present invention, a stabilizer can be placed on the casing immediately adjacent the drill bit, and consequently the entire assembly may be moved in a straight line relative to the drill hole and such alignment maintained as drilling proceeds. If the conventional down-hole motor assembly has a stabilizer placed on the inner turning member, where the bit is attached, which is often done, it tends to merely follow the bit with little assistance in maintaining a straight hole, which is the primary purpose for the stabilizer.

Drill assemblies in accordance with the invention will find particular utility in the offshore drilling of a well or the sampling of submerged land to determine geological or mineralogical data. In such environment the stability and direction for the drilling operation may be effected through a drill guide frame or supporting frame which rests on the bottom of the body of water at the drilling location and is suspended by guide lines from either a platform or a workboat located above the drilling site. The drill bit assembly is supported by such supporting frame and fluid is supplied by a flexible hose, thereby eliminating the necessity for the meticulous and continuous positioning of the vessel, as is the case where rigid drill pipe is employed. The arrangement also has the advantages of simplicity and the dissipation of vibrations into the water. A preferred drill guide frame is characterized by parallel vertical guides which support and define the direction of movement of the drilling assembly, as well as provide a means for holding the inner part of the motor against rotation. Alternatively, the guide frame may comprise a support made up of a series of interlocked crossmembers, the drilling being accomplished through an opening between the members. Basically, the es sential requirement is the provision of a support for the drilling assembly such that it will be maintained in a vertical position. Of course, rigid pipe may be employed, in which event the drill guide frame is not required. It is also within the spirit of the invention to employ a flexible hose to supply the driving fluid for the bit motor in a land drilling operation, in which event bore engaging means will be provided to hold the inner gear member against rotation.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation, parts of which are in section, of a complete operative system employing the novel features of this invention.

FIG. 2 is a cross-sectional side elevation of a portion of the structure taken along line 2-2 of FlIG. l.

FIG. 3 is an enlarged detailed vertical cross-sectional view of the drilling mechanism showing the fluid motor and the connections for holding the inner helical gear of the motor against rotation.

FIG. 4 is an enlarged vertical cross-sectional view similar to FIG. 3 but showing the lower part of the fluid motor and a coring drill.

FIG. 5 is a cross-sectional view taken along lines 5-5 of FIG. 1.

FIG. 6 is an enlarged vertical cross-sectional view similar to FIG. 3 but showing a modified connecting member.

FIG. 7 is a view similar to FIG. 2, parts of which are shown schematically, but illustrating a second embodiment.

FIG. 8 is an enlarged partial vertical cross-sectional view showing a modification of the drilling assembly.

FIG. 9 is a top view of the structure shown in FIG. 8, but with parts removed. 1

FIG. 10 is a side elevational view, with parts broken away, of a fitting for engaging the walls of a bore.

DESCRIPTION OF THE INVENTION Turning now to a detailed consideration of the invention, it will be recalled that the invention is, among other things, particularly adapted to the sampling or exploration of submerged land, and for convenience it will be so described. However, this should not be read as a limitation on the invention, as it is applicable to the depth limit of conventional drilling rigs over land or water, and in water of unlimited depth by means to be described hereinafter.

Referring now in greater detail to the drawings, an application of this invention to offshore operation is shown in FIG. 1.

. As indicated previously, a typical offshore drilling operation is directed from a platform or workboat 1, which is provided with a crane 2, a hoist 3, and a pump 4. Suspended from the hoist 3 are guidelines 5, one end of which are connected to a drill guide frame 10 which positions and directs the actual drilling operation.

The novel features of this invention, illustrated in detail in FIGS. 2-5, are the means whereby the drilling is accomplished in a simplified manner. The support for the drill is achieved through the drill guide frame 10 which is weighted at base 11 so as to rest in a substantially vertical position. Extending from the base 11 are support members 12 which provide for a passage 13 within which the drilling mechanism 14 operates. It should be clear that numerous modifications may be made in the construction of the drill guide frame 10 to accomplish its intended purpose. For example, the guide lines 5 along which the drilling mechanism 14 may be moved, can be embedded in the base 11. While it is not shown, it should also be apparent that guide bars could replace the guidelines 5 in the area of guide frame, with the guidelines 5 suspended from a structural member located at the top of the drill guide frame 10. In either case, means such as the cable 15 operative from crane 2 are provided whereby the drilling mechanism 14 can be moved or caused to reciprocate in a vertical direction within the drill guide frame 10.

The primary drilling mechanism 14, shown in detail in FIGS. 3-5, comprises a liquid motor and universal joint assembly A" and a core barrel assembly B. The liquid motor, as best seen in FIGS. 3 and 4, comprises a casing mounting an outer member 21 which may be resilient and which has a double helical internal thread. Contrary to the ordinary operation of such a liquid motor, the outer member 21 is free to rotate along with its surrounding casing 20. Within the outer member 21 there is disposed an inner member 22 which operatively engages the internal threads of the outer member 21 as the latter rotates thereabout. As taught in the aforementioned US. Pat. No. 2,898,087, the passage of liquid through the helical passageway 23 in the outer member causes the relative movement between the outer and inner members; and since in accordance with the present invention the rotating outer member is the means whereby the drill bit is caused to rotate, its direction of rotation will be such that standard drill bits may be employed.

As will appear from a study of the Moineau patents, the relative movement between the gear members is eccentric to 5 the axis of the outer member. This would account for the nonalignment of the axis of the inner member 22 to the axis of the outer member 21, as illustrated in FIG. 3. Therefore, in order to secure the upper end 24 of the inner member against rotative movement, and to provide for the eccentric positioning of upper end 24, a connecting member 25, in the form of a double universaljoint, is provided to secure end 24 to concentric stationary member 26. The latter member is provided with a bore 27 which communicates with the chamber 28 by means of passages 29. Hence, the liquid for driving the liquid motor is pumped through the bore 27 into chamber 28 defined by the surrounding section of casing 30, whereupon it is caused to enter the helical passageway 23.

At the upper portion of FIG. 3, there is shown the means whereby the assembly A" is free to rotate about the stationary member 26. To this end, the stationary member 26 mounts lower and upper sets of annular bearings 32 and 33, respectively, each such set of bearings comprising outer and inner bearing members 40, 41 having an intermediate set of ball bearings 42. The sets of bearings thus rotatably journal the casing sections 20 and 30, together with the casing section 43 surrounding the stationary member 26, for rotative movement relative to the member 26 which, at its upper end, is fixedly secured by means of fitting 44 to a section of casing 45 which is held against rotation in one of several ways which will be hereinafter described. While the foregoing is exemplary of the means to effectively facilitate the rotative movement of the outer helical gear member 21, it should be apparent that other and different types of bearings may be employed. But in any case, by providing for the bearing points at these locations in the drilling mechanism, the pressures and resulting stresses normally found at or around the drilling bit are avoided, especially in using the embodiments in which a flexible hose is connected to the drill assembly.

The coring apparatus shown in detail in FIG. 4 is not novel per se. However, it is illustrated here as it is particularly suited for core sampling of submerged land. The arrangement of the mechanism of FIG. 4 is such that it can cut through the surface of the earth, extract, and then retain a consolidated core in the bore 46 of core barrel B.

The direction of the drilling and sampling operation is controlled by a guide means 50, which is shown in detail in FIG. 5. The guide means 50 is characterized by a collar 51 in which the core barrel is slidably received. Extending from the collar 51 are guide arms 52 which are provided with means for receiving vertical guides, such as guidelines 5. In the embodiment shown in FIG. 5, the latter means comprises ears 53 con taining holes 53a through which guidelines 5 pass. However, if guide bars were used in place of the guidelines, ears 53 could contain bar engaging slots. To insure against any vibration or chatter of the drilling mechanism, the collar 51 may be provided with a resilient radial bearing 54 held in place by a series of set screws 540 which locate the radial bearing within the opening 51 so as to permit the drill to move vertically within the guide collar.

At the upper part of the drilling mechanism, a torque arm 55, similar to the construction of the guide means 50, is fastened to the drilling mechanism. The torque arm 55 is secured to the uppermost portion C of the drilling mechanism at a point above the bearing elements 32, 33 to hold the drilling mechanism against rotative movement. Otherwise, the entire mechanism would rotate and thus be ineffective. Thus, as seen in FIGS. 1 and 2 the torque arm 55 may be arranged to engage the support members of the drill guide frame 10 and/or the guidelines 5, the salient consideration being to hold the portion C against rotation and yet permit vertical movement of the drilling mechanism. With reference to FIG. 3, the section of casing 45 may comprise the portion C;" and it will be evident that if the casing 45 is held against rotation, the concentric member 26 is also held against rotation. A further feature of the torque arm 55 is to maintain the drilling mechanism in an essentially vertical position, the torque arm coacting with the guide means 50 to insure straight line boring in a vertical direction.

The typical offshore drilling platform or workboat I is pro vided with some means for directing the drilling operation several hundred feet below the surface of the water. In the illustrated embodiment, such means include a crane 2, hoist 3, and pump 4. The crane and hoist work together in positioning the guide frame and drilling mechanism at the drill site. That is, the hoist 3, by means of guidelines 5, can be used to lower the drill guide frame to a position on the oceans floor at the drilling site. With the particular method contemplated herein, it is possible to use constant torque drums on the drilling platform or workboat 1 so as to operate the guidelines uniformly. Where the drill guide frame is employed, it is not necessary to have conventional drill pipe extending downwardly from the workboat so that there is effectively a rigid connection between the workboat or the like and the drilling mechanism. Rather, a flexible hose 60 may be employed to supply driving fluid for the drill motor, and the crane 2, which is utilized to position the drill guide frame, also may be utilized to support the flexible hose, as will be evident from FIG. 1. Since water under pressure is sufficient to drive the liquid motor, the surrounding water, which is in ample supply, may be used. Water is received into the system by means of pump inlet 4a and pumped by pump 4 through hose 60 into the portion C" ofthe drilling mechanism described above.

The pressure of the water passing through the drill motor, in which the inner helical gear member 22 is fixed against rotative movement, causes the outer helical gear member 21 and the drill bit to rotate. The passage of the water is completed by exiting through the drill bit where it is discharged.

While the foregoing arrangement eliminates the necessity for a string of rigid drill pipe extending between the drilling platform or workboat, it should be evident that such drill string may be employed if desired, in which event the casing 45, shown in FIG. 3, may comprise the lowermost section of the drill string, it being understood that in such event the drill string will be nonrotatively secured at its uppermost end. This does not mean, however, that the drill guide frame need be discarded. Rather, the drill guide frame may be retained as a positioning and guiding means for the drill string, the drill string being free to move vertically through the openings in the collars 50 and 55 as drill pipe is added to the upper end of the string.

Another important feature of the invention liesin the fact that the conventional double universal joint 25 which connects the inner helical gear member 22 to the concentric sta' tionary member 26 may be replaced either by a torsion bar made of spring steel, or a wire cable. This is due to the fact that the inner helical gear does not rotate, but rather simply gyrates in a circular path and hence can be held against rotation by any member which is sufficiently flexible to permit the inner helical member to gyrate without rotation. Thus, as illustrated in FIG. 6, wherein like parts have been given like reference numerals, the inner helical member 22 is held against rotation by means of the flexible cable 61 fixedly secured at its lowermost end to the upper end of member 22 and fixedly secured at its uppermost end to the lower end of stationary member 26. Where a twisted wire cable is employed, it is preferred that the direction of the twist of the cable will correspond to the direction in which the member 22 gyrates so that the gyrating movement will act to maintain the cable in tightly twisted condition and resist any tendency to unwind. Alternatively, a braided cable may be employed. Where a spring steel torsion bar is used, it need only be sufficient size and resiliency to hold the inner helical member against rotation while permitting it to gyrate. Such constructions are far simpler and at the same time avoid the problems of wear and lubrication encountered where universal joints are employed. In addition, since the connecting member is under tension rather than compression, limitations heretofore imposed on length and mass of the connecting are eliminated due to the fact that the connection is under tension and hence does not have to sustain the loads encountered in down-hole 5 motor drilling assemblies, such as those taught in the afore mentioned U.S. Pat. No. 2,898,037.

The instant invention also facilitate the out: of tstnhilmzm immediately adjacent the drill bit, as indicated at 8| in MG. 0. Heretolore such stabilizers have, of necessity, been positioned remote from the bit to avoid binding. However, since the en tire drill mechanism, i.e., the casings making up sections A" and B," are rotating a stabilizer can be mounted immediately adjacent the bit. Such stabilizers may be conveniently mounted to rotate with the casing, although it may be found that in certain formations of earth the stabilizers could be inwardly surfaced with a so-called marine bearing of resilient material having grooves for fluid lubrication. In such event, the stabilizer would be allowed to remain stationary or rotate, at will, or it could be made in its entirety of resilient material and loosely slipped over the casing and allowed to remain static, being held by the greater resistance of the hole wall.

It should be clear that modifications may be made in the invention described herein without departing from the spirit and scope. For example, the apparatus of this invention may be adapted for any kind of boring other than in earth. Further, as indicated above, it is the pressure causing the water to pass through the drilling mechanism which results in the relative movement between the inner and outer members. However, other mediums under pressure can also be employed to drive the motor. FlG. 7 is a simplified representation of such a modification. It will be noted that the only connections with the working platform are the guidelines. That is, the flexible hose 60 and pump 4 have been eliminated and replaced by a portable powering means 62, such as a cylinder, mounted on the drilling mechanism 14a and opening into the upper part C" through a valve that is opened by a control arm 63 striking a portion of the support structure 12a or ocean floor.

In the modified embodiment shown in FIG. 7, it will be seen that the cylinder is mounted on a support member 12a with a conduit 64 connecting same to the drilling mechanism. Since the source of pressure for the motor driving medium is the cylinder, it should be understood that the motor is operative to drive the drill bit only until such time as the cylinder is empty. However, this should be sufficient to effect the necessary sampling or drilling.

The power can be furnished by the cylinder in several ways. For example, the cylinder could be empty and lowered into position such that by the opening of the cylinder valve, the inrush of water, particularly at great depths, would power the drill with a reverse circulation until such time as the cylinder has been filled. While this is essentially the principal of the operation, this powering method can be modified to the extent that the water inlet may be varied depending on the depth of the operation. That is, a smaller inlet opening would be required at the greater depth so as to avoid destruction of the device.

A second method, which may be preferable for shallow water drilling, would be one resulting from a cylinder filled with air or other gas under pressure, such that with the opening of the cylinder the motor would be driven just like the compressor or pump which is located] above the surface of the water. In order to seal the contact of the inner and outer mem bers, it may be preferable to use a two-part cylinder with water in the lower part to form the actual drive for the motor. The second part would be air or gas which would force the water downward through the motor. Another method of sealing with water would be to pump a small stream of water into the system from above at the same time the cylinder is being exhausted.

A further powering method which may be used in either shallow or deep water would be a cylinder containing a chemical which is known to create a gas upon contact with water. Thus, by opening the valve exposing the chemical to the water, a gas would be generated which could be utilized to drive the mechanism directly or through a water film or body such as described above.

In utilizing the self-contained power source as outlined above, it is possible to eliminate one component of the structure shown in FIG. 4. For example, where the operator is satisfied with merely a sample of the drilled cuttings and does not require a consolidated core, such as would be received in the bore 46, the structure can be modified by the removal of the core barrel. That is, an ordinary bit can be used in place of the hollow core bit. Specimens of the cutting will be deposited by the water flowing into the empty cylinder 62.

Still another modification of this invention is illustrated in FIGS. 8 and 9. In brief, FIG. 8 may be considered a simplification of the structure shown in FIGS. 3 and 4. It will be recalled that in order to secure the upper end 24 of inner member 22 against rotative movement, connecting members were employed. However, in this new embodiment, the last named members have been eliminated and means 70 are used directly to secure end 24 against rotation. Means 70, for convenience, may comprise arm portions threadably secured to the head 71 and containing at the outer ends thereof means 72 for slidably engaging guide bars 73. As explained above, the engaging means may be an elongated hole, slot or similar means. The preferred means would be a slot which is rubber padded to minimize wear.

It should be apparent from FIGS. 8 and 9 that the relationship between the nonrotating member 71 and the rotating casing 74 is eccentric. Therefore, as the casing 74 carrying the drilling bit rotates, the head 71 gyrates but does not rotate. To facilitate this gyrating movement, the rubber padded means 72 works loosely about the guide bars 73. The direction of gyration of the head is in the opposite direction to its tendency to rotate. In this case, it would be in the same direction as the movement of the outer outer 74.

In the embodiment shown in FIGS. 1-5, it will be seen that the guide means or torque arms were used as means to help guide the structure. In the latter embodiment, similar but modified supports are employed. Since the casing within the upper ring 75 is rotating, said ring must be constructed so as to permit unrestricted movement. The annular portion 76 is provided with a ball receiving channel or groove 77 opposite a similar groove 78 in the outer casing wall 79. The use of balls 80 riding in the respective grooves 77 and 78 permits the movement of the casing, yet retain the ring 75 in a supporting position about the drilling mechanism. If it is desired to pass the drilling assembly through the support structure entirely, the upper ring 75 must be replaced after it reaches the bottom of the structure with a loose fitting collar in a guide bar and the same change made on guide means 50, so that allowance is made for the drilling assembly to pass through the structure into the bore hole. This system would therefore provide means for reentry after renewing bits and, in coring, after removing cores and/or renewing core bits. After the drilling assembly passes below the support structure, the bore hole supports the assembly. Torque arm 70 is then no longer needed and must be removed, being replaced by the bore engaging mean hereinafter described.

As should now be apparent, drilling apparatus in accordance with the invention may be used both on land and in water. When used on land, the coring or drilling apparatus, such as that illustrated in FIGS. 3, 4 and 6 can be lowered downwardly in the bore on a rigid pipe and the inner member held against rotation by holding the pipe at the surface. A drill guide frame may be used for land drilling with or without a conventional rig, except that on land the weighted base would not be required. However, unless a conventional rig is employed, a boom derrick or other means would be required to handle the motor and pipe in and out of the structure. Drill pipe for extension down the bore can be added above the motor as in the conventional manner when employing a down hole motor," or such pipe may be added below the motor, i.e., between the motor and bit. If the motor is retained at the surface, it will be evident that in deeper holes the addition of pipe below the motor will add to its load and hence the addition ofpipe will be limited by the power of the motor.

The drilling mechanism can be lowered downwardly into the bore on a wire line and the inner member held against rotation by hydraulically forcing outwardly two or more pistons, using the drilling fluid pressure, the pistons having rollers at their outer cnds positioned to move vertically up and down the bore walls, pressing tightly against them. Such an arrangement is illustrated in FIG. 10 wherein the fitting 81 mounts opposed pistons 82 having rollers 83 at their outermost ends adapted to engage the bore walls. Hydraulic power will be introduced into the passageway 84 through the flexible hose 60 in the manner illustrated in FIG. 1, the fitting being provided with a swivel hose connection 85 which will serve to prevent hose twist before the pistons are set. At its lower end the fitting is provided with a threaded pin 86 by means of which the fitting 81 may be connected to the fitting 44 shown in FIG. 3 or to the head 71 shown in FIG. 8. Preferably, the rollers 83 will be tapered in cross section, having a relatively sharp circumference which will present a sharp contact line to the walls of the bore, thereby effectively holding the inner member against reactive torque and enabling the outer member to rotate. Such fitting may also be employed for undersea drilling unless the operator prefers to retain the motor observable by a diver, or in case of shallow bores, when hydraulic fluid is pumped down through a hose and drill pipe is added below the drilling assembly in which cases the drill guide frame would be employed.

It should thus be evident that the instant invention may be utilized under diverse drilling conditions and is readily susceptible to modification to adapt to whatever operating conditions are encountered. It should also be clear that the invention is equally applicable to drilling and coring, the latter comprising a specific form of drilling which the center of the cut is left intact. Similarly, it will be evident that when reference is made to a drill bit, it would encompass a core barrel with a core bit for coring operations. Likewise, reference to pipe or drill pipe is inclusive of casing and drill collars, the latter being essentially a heavy wall pipe utilized to add bit weight.

The various embodiments can be constructed with or without connecting rods, arranged with or without support structures, used with conventional land rigs, platform rigs or ship rigs; employed with rigid pipe or flexible hose for power conduction, used with the drilling assembly above or in the bore hole; and, operated to any depth consistent with the physical capabilities of the auxiliary equipment used in the art.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Drilling apparatus comprising a drill housing containing a fluid motor, said motor including inner and outer interrneshed helical gear members, means connected to said inner gear member to hold it against rotation, said outer member being free for rotative movement about said inner gear member, and means for mounting a drill bit operatively connected to said outer gear member for rotation therewith.

2. The drilling apparatus claimed in claim 1 wherein said drill housing comprises a first section of casing rotatable with said outer gear member, a second section of easing overlying and operatively connected to said first casing section, bearing means mounting said first casing section for rotation relative to said second casing section, and means securing said second casing section against rotation.

3. The drilling apparatus claimed in claim 2 wherein the means for holding said inner gear member against rotation comprises a connecting member extending between and operatively connecting said inner gear member to said second casing section.

4. The drilling apparatus claimed in claim 3 including stabilizing means operatively connected to said first casing section adjacent said drill bit mounting means.

5. The drilling apparatus claimed in claim 3 wherein said connecting member comprises a connecting rod having universal joints.

6. The drilling apparatus claimed in claim 3 wherein said connecting member comprises a torsion bar.

7. The drilling apparatus claimed in claim 3 wherein said connecting member comprises a wire cable.

8. The drilling apparatus claimed in claim 3 wherein said inner gear member is rigidly connected to said second casing section, and wherein said bearing means mounts said second casing section for gyrating movement relative to said first casing section.

9. The drilling apparatus claimed in claim 2 including a drill guide frame mounting said drilling apparatus for vertical movement.

10. The drilling apparatus claimed in claim 9 wherein the means securing said second casing section against rotation comprises a fitting operatively connecting said second casing section to said drill guide frame.

11. The drilling apparatus claimed in claim 10 including a power source for driving said fluid motor.

12. The drilling apparatus claimed in claim 11 wherein said power source is mounted on said drill guide frame.

13. The drilling apparatus claimed in claim 9 including guide means for positioning said drill guide frame relative to a remote operating platform overlying the drilling site.

14. In combination in well drilling apparatus, a fluid motor having intermeshed inner and outer helical gear members,

means mounting said outer gear member for rotation relative to said inner gear member, means mounting said inner gear member against rotation but permitting it to gyrate in a circu lar path eccentric with respect to the axis of rotation of said outer gear member, and drill bit mounting means operatively connected to said outer gear member for rotation therewith.

15. The combination claimed in claim 14 wherein said outer gear member is fixedly secured to a first casing section, wherein said drill bit mounting means is operatively connected to said first casing section, and wherein the means mounting said inner gear member against rotation includes a second casing section which is held against rotation, said first casing section being rotatablyjournaled to said second casing section.

16. The combination claimed in claim 15 wherein a concen tric shaft is nonrotatively connected to said second casing section, and wherein said first casing section in part surrounds and is rotatably journaled to said concentric shaft by means of spaced sets of bearing interposed between said first casing section and said concentric shaft.

17. The combination claimed in claim 16 wherein the means mounting said inner gear member against movement also includes a connecting member operatively connecting one end of said inner gear member to said concentric shaft.

18. The combination claimed in claim 17 wherein said connecting member is sufficiently flexible to permit gyrating movement of said inner gear member and yet sufficiently resistant to torque forces to prevent rotation thereof. 

1. Drilling apparatus comprising a drill housing containing a fluid motor, said motor including inner and outer intermeshed helical gear members, means connected to said inner gear member to hold it against rotation, said outer member being free for rotative movement about said inner gear member, and means for mounting a drill bit operatively connected to said outer gear member for rotation therewith.
 2. The drilling apparatus claimed in claim 1 wherein said drill housing comprises a first section of casing rotatable with said outer gear member, a second section of casing overlying and operatively connected to said first casing section, bearing means mounting said first casing section for rotation relative to said second casing section, and means securing said second casing section against rotation.
 3. The drilling apparatus claimed in claim 2 wherein the means for holding said inner gear member against rotation comprises a connecting member extending between and operatively connecting said inner gear member to said second casing section.
 4. The drilling apparatus claimed in claim 3 including stabilizing means operatively connected to said first casing section adjacent said drill bit mounting means.
 5. The drilling apparatus claimed in claim 3 wherein said connecting member comprises a connecting rod having universal joints.
 6. The drilling apparatus claimed in claim 3 wherein said connecting member comprises a torsion bar.
 7. The drilling apparatus claimed in claim 3 wherein said connecting member comprises a wire cable.
 8. The drilling apparatus claimed in claim 3 wherein said inner gear member is rigidly connected to said second casing section, and wherein said bearing means mounts sAid second casing section for gyrating movement relative to said first casing section.
 9. The drilling apparatus claimed in claim 2 including a drill guide frame mounting said drilling apparatus for vertical movement.
 10. The drilling apparatus claimed in claim 9 wherein the means securing said second casing section against rotation comprises a fitting operatively connecting said second casing section to said drill guide frame.
 11. The drilling apparatus claimed in claim 10 including a power source for driving said fluid motor.
 12. The drilling apparatus claimed in claim 11 wherein said power source is mounted on said drill guide frame.
 13. The drilling apparatus claimed in claim 9 including guide means for positioning said drill guide frame relative to a remote operating platform overlying the drilling site.
 14. In combination in well drilling apparatus, a fluid motor having intermeshed inner and outer helical gear members, means mounting said outer gear member for rotation relative to said inner gear member, means mounting said inner gear member against rotation but permitting it to gyrate in a circular path eccentric with respect to the axis of rotation of said outer gear member, and drill bit mounting means operatively connected to said outer gear member for rotation therewith.
 15. The combination claimed in claim 14 wherein said outer gear member is fixedly secured to a first casing section, wherein said drill bit mounting means is operatively connected to said first casing section, and wherein the means mounting said inner gear member against rotation includes a second casing section which is held against rotation, said first casing section being rotatably journaled to said second casing section.
 16. The combination claimed in claim 15 wherein a concentric shaft is nonrotatively connected to said second casing section, and wherein said first casing section in part surrounds and is rotatably journaled to said concentric shaft by means of spaced sets of bearing interposed between said first casing section and said concentric shaft.
 17. The combination claimed in claim 16 wherein the means mounting said inner gear member against movement also includes a connecting member operatively connecting one end of said inner gear member to said concentric shaft.
 18. The combination claimed in claim 17 wherein said connecting member is sufficiently flexible to permit gyrating movement of said inner gear member and yet sufficiently resistant to torque forces to prevent rotation thereof. 